Diabetes is a disease impairing a person's ability to produce or respond to insulin, thus elevating levels of glucose in the blood. Diabetes can cause long term and serious problems, including multiple organ failure, heart attack, blindness, amputation and nerve damage. One way diabetics monitor their blood glucose levels is by using diabetes test strips, which work by converting glucose in the blood into an electrical current. Each test strip has a unique formulation of enzymes that works as a catalyst. Present day test strips use various chemistries, such as GDH-PQQ with nPBI inhibitor mediator (Osmium complex with n-pentyl benzimidazole ligand) or GDH-FAD with MAP mediator n-methyl pyridine. Typically, a test sample of blood is obtained from the user, approximately 0.3 microliters. An electrical current is produced on test strip and travels on gold plated circuits to be converted into an electrochemical signal for the glucose meter to display. Details of the workings of a glucose meter may be found, for example, in Dr. Erika Gebel, Electrochemical Test Strips, DIABETES FORECAST, 2012.
Since diabetes is a long term disease spanning the lifetime of the diabetic, many test strips are used by the diabetic throughout his or her lifetime. For example, type 1 diabetics may take as many as 30 glucose readings daily. Test strips are expensive, usually costing $0.40 to $1.00 each, and in some cases as much as $2.00 each. As such, test strips which become unusable for a variety of reasons, as set forth below, can cost the diabetic a substantial amount of money. Moreover, diabetes test strips are susceptible to counterfeiting and inaccurate test readings. Inaccurate readings can have a substantial impact, including altering administered dosage levels, as well as medical implications such as, loss of eyesight, liver and kidney damage, and poor circulation. Poor circulation in diabetics has long resulted in loss of limbs, especially feet. Medical implications for incorrect dosages based on erroneous readings have even resulted in death in some cases.
Presently, test strips and particularly blood glucose test strips are sold loosely packed in plastic containers. Usually there are 50 strips in a container and the individual strips are difficult to access due to crowding. During the process of removing a single test strip for insertion in a separate glucose meter, the test strip may be compromised through contact with unsterile handling, such as with human fingers or by dropping it on the table or the ground from the container, thus resulting in contamination which can cause inaccurate or voided test readings.
Recalls also are a problem in the industry. In most cases, there are no issues with respect to manufacturing, but over time exposure to moisture and temperature variances and vibrational forces (see below) can lead to test strip degradation and failure. Historically, there have been recalls of test strips involving low readings that could cause a type 1 diabetic to over medicate, thus resulting in diabetic ketoacidosis.
For example, the transportation of test strips by land carrier, where there are road vibrations and exposure to G Forces from potholes and road bumps, as well as bearing and spring vibrations from vehicles and forklifts, may affect test strip enzyme performance due to the damage of the delicate enzymes present in the test strips. Interestingly, the fruit industry is acutely aware of this phenomenon and has underwritten many scientific tests to investigate cellular (enzyme) degradation from fruit transit. In one study, the placement in the truck of the boxes of fruit to be shipped was analyzed, and it was determined that boxes placed at lower levels experienced more degradation after shipment and careful testing. See Ran Zhou et al., Effect of transport vibration levels on mechanical damage and physiological resposnes of Huanghua pears, 46 POSTHARVEST BIOLOGY AND TECHNOLOGY 20-28 (2007). Tests on the degradation of enzymes of fruit during transport may also shed light on the effect of vibration on diabetes test strip failure.
Moisture is also a factor. The enzymes in the test strip are delicate and need to be hydrated and maintained in a specific moisture range for the test strip to perform properly or they will fail. Too much hydration will lead to degradation of the strip. Further, test strips are sensitive to temperature. Most test strips should be maintained at temperatures above at least 4 degrees C. and below 30 degrees C., and exposure to temperatures outside of this range can damage the enzymes.
Black and grey market test strips are also a major problem in the industry. Sales of black and grey market diabetes test strips result in significant lost revenue and profit. In the grey market, U.S.-based manufacturers of diabetes test strips ship these products outside of the United States for sale abroad. In some instances, these diabetes test strips are illegally imported back into the United States and sold to pharmacies for resale to the public. About 95% of all of these gray market sales are paid for by third-party insurance and the United States government, through Medicare or Medicaid, resulting in the loss of billions of dollars each year. Indeed, the quality of such grey market test strips and their handling are called into question and raise legal ramifications as well, where it is most likely that insurance companies, Medicare, or Medicaid paid for those test strips in the first place. On the other hand, in the black market, entirely counterfeit test strips are also a clear danger to a diabetic person, resulting in inaccurate readings, including low or high readings that cause an over or under medication, resulting in injury or even death.
Another issue with current diabetic test strip packaging is that present test strip containers are not ecologically viable. Test strips and test strip containers are used by the hundreds of millions each year and discarded into landfills. Most containers are made from plastic, which are often not recyclable and find their way to a waste dump.
Current packaging arrangements for test strips fail to meet patient needs for ensuring quality glucose readings. Several attempts have been made to solve some of the above-mentioned problems, such as those found in International Patent Application Publication No. WO 2009/053437 to Eisenhardt et al., U.S. Patent Application Publication No. 2012/0203465 to Callewaert et al., Chinese Patent Publication No. 103228305 to Day et al., and International Patent Application Publication No. WO 2005/040793 to Griffith et al. However, none of these attempts entirely solves the issue of quality degradation of test strips or gray market sales and counterfeiting.
As such, there exists a need for reliable device packaging for a glucose measurement system, including for diabetes test strips, that improves glucose level accuracy while reducing the potential for counterfeiting to protect the health of patients.